1. Field of the Invention
The present invention relates to an image processing method. More particularly, the present invention relates to a method for automatically rectifying business card presentation angle.
2. Related Art
In social communication occasions, people often use business cards to express their personal information and develop interpersonal relationships by exchanging the business cards. With the expansion of social relationships, the business cards are increasingly accumulated, and thus the business card management becomes quite important. In the past, the business card management is usually collecting and organizing the business cards into booklets. However, in order to look up personal information of a contact person, the business card of the contact person still has to be searched for in the piles and booklets of business cards, which is against the requirements of high-efficiency mobile commerce. With the coming of the electronic age, in most circumstances, data on each business card is built into a database through a computer, and the business card data of a wanted contact person can be easily found by keying in the name of the contact person. However, it is a bit slow to key the business card data one by one into the computer database. Thereby, a business card recognition (BCR) technique is put forward to enhance the business card management efficiency, in which business cards are scanned by an optical recognizer, or shot by an optical lens to obtain card images, and then the information on the business cards is captured and automatically input into a computer database.
Currently, many mobile electronic devices, such as mobile phones and personal digital assistants, all apply the BCR technique. Business cards are shot by a lens module built in a mobile electronic device to obtain card images, and then the information on the business cards is analyzed to construct a mobile business card database in the mobile electronic device. However, the BCR technique applied in the mobile devices often leads to recognition failure or error due to the shooting angle. For example, when a hand-held mobile electronic device is used to shoot a business card, a departure of the shooting angle may occur at the moment the shoot button is pressed. As a result, the presentation angle of the shot card image is oblique and is hard to recognize. In some mobile devices, a plurality of border lines is provided in the viewing window or display screen for the user to correct the shooting angle of the business cards. The mobile electronic device shoots only after the shooting angle is corrected into an acceptable range of the BCR system. However, such method still cannot eliminate the departure of the shooting angle occurring at the moment the shoot button is pressed. Moreover, in some mobile devices, a user interface is provided for the user to circumscribe the part of the shot business card image to be corrected after shooting. Such correction has to be performed in certain steps. The elders or those unfamiliar with the operation cannot easily carry out the business card recognition. In addition, for some mobile devices, the placing angle and position of a business card are determined according to the color difference between the business card and the background, and the shot image of the business card is automatically corrected, so as to improve the accuracy of capturing the information on the image of the business card. However, it is difficult for the elders or those unfamiliar with the operation to get accustomed to the manner of providing the user with border lines to assist the correction of the shooting angle or with a human-machine interface to select the recognition range. Besides, the manner of automatically correcting the image angle through the color contrast between the business card and the background may not successfully rectify the business card image as the background is too white, thus resulting in the failure of business card recognition.